Thermodynamic properties of quasi-equilibrium magnons in crystalline bulk materials and thin films

The temperature dependence of spontaneous magnetization and specific heat for a system of magnons are investigated systematically. The correspondence of this system with the Bose-Einstein condensation phenomenon is used. Calculations are performed for both crystalline bulk materials and thin films. The calculated results are consistent with the available experimental data, indicating that our suggested approach is a suitable one for describing the thermodynamic properties for the magnon system. The thermodynamical parameters for magnons system have many similarities with the thermodynamical parameters for boson atomic gas. Results for crystalline bulk material can be used as a zeroth order approximation in any perturbative treatment of thin film. In contrast to a previous study, our method involves only analytic calculations.